Over the past year the research work on ferromagnetic silicone occlusion for cerebral aneurysms and hypervascular neoplasms has progressed so that it has been applied in six (6) cerebral aneurysms successfully, coating the aneurysms internally and/or externally. In addition, as a result of clear demonstration that solid organs could be completely destroyed or partially destroyed as the case may be, the technique has been applied to a hypernephroma of the lower pole of one kidney. This kidney was removed several hours after the thrombosis and pathologic tests showed that the kidney's tumor was necrotic in its central portion and showing evidence of progressive necrosis peripherally. Current efforts are continuing to explore the possibility of applying such a technique for ferromagnetic silicone thrombosis with the addition of radioactive P32 for the destruction of peripheral lung tumors. This can be accomplished in animals by injection of a segment of the pulmonary artery. The vulcanized mass of silicone will then cause the necrosis of the tissue in the distribution of the pulmonary artery, and by radiation, destruction of the bronchial arteries and lymphatics. Work is going forward to develop small arterial catheters for the treatment of arterio-venous malformations in the brain and elsewhere.